Verifying Coulomb's Law: Q1, Q2 & R

[Tony Tesla]

Hi, Can someone help me with this question? I understand Coulomb's law but i want to know if I am doing it right.
So the charge of
Q1= 2 mC
Q2= 1 mC
And R= 5 cm (0,05m)
This is how i solved it.
F= K(8,988x10^9) x (2x10^-6)x(1x10^-6) / (0,05m)^2
F= K(8,988x10^9) x 8x10^-10
F= 7.1904 N

Is 7.1904 the right answer?

 

[Tanya Sharma]

Hi, Can someone help me with this question? I understand Coulomb's law but i want to know if I am doing it right.
So the charge of
Q1= 2 mC
Q2= 1 mC
And R= 5 cm (0,05m)
This is how i solved it.
F= K(8,988x10^9) x (2x10^-6)x(1x10^-6) / (0,05m)^2
F= K(8,988x10^9) x 8x10^-10
F= 7.1904 N

Is 7.1904 the right answer?

Hi Tony Tesla...

Welcome to PF!

1mC = 10^-3C , not 10^-6C

Please recheck your calculations.

 

[Tony Tesla]

Submultiples Multiples
Value Symbol Name Value Symbol Name
10−1 C dC decicoulomb 101 C daC decacoulomb
10−2 C cC centicoulomb 102 C hC hectocoulomb
10−3 C mC millicoulomb 103 C kC kilocoulomb
10−6 C µC microcoulomb 106 C MC megacoulomb
10−9 C nC nanocoulomb 109 C GC gigacoulomb
10−12 C pC picocoulomb 1012 C TC teracoulomb
10−15 C fC femtocoulomb 1015 C PC petacoulomb
10−18 C aC attocoulomb 1018 C EC exacoulomb
10−21 C zC zeptocoulomb 1021 C ZC zettacoulomb
10−24 C yC yoctocoulomb 1024 C YC yottacoulomb
Common multiples are in bold face.

Source: http://en.wikipedia.org/wiki/Coulomb

I think it is 10^-6

Now i see it i typed Mc instead of μC
Sorry

 

[Tony Tesla]

Hi Tony Tesla...

Welcome to PF!

1mC = 10^-3C , not 10^-6C

Please recheck your calculations.

I see now, I ment μC not mC sorry.

 

[Tanya Sharma]

I see now, I ment μC not mC sorry.

Even then your calculations are wrong.

Recheck...

 

[Tony Tesla]

Even then your calculations are wrong.

Recheck...

checked it 5 timed every time the answer was 7.1904 N
After that i went to this page: http://www.endmemo.com/physics/coulomb.php
and the answer there was also 7.1904 N

 

[ehild]

The solution for the force is correct if the charges are given in μC .

ehild

 

[Tony Tesla]

The solution is correct if the charges are given in μC .

ehild

Thank you

 

[Tanya Sharma]

Yes...your solution is correct.I misread the given data.